Remington Sendero 7mm RUM and 180 gr Berger VLD?

Yes US869 is not a good option if you have a big difference in temps say from when you developed your load til the time you hunt, if you are a hunter. I tried it once in my gun and knew right away it would not work here in Idaho for me. You also have the option of installing a wyatt extended box magazine as that will give you a little more wiggle room in your magazine for a longer load. They are very easy to install if you have a dremel tool. Retumbo or H1000 worked the best for me. But again that was in the 300RUM.
Good luck

Not having first hand experience with this caliber, this is only my opinion.
I am fairly certain you will not expeirence any stabilization problems with that little difference in twist rate. I know guys are shooting the 240gr SMK out of their sendero 300RUM's and they have a 1/10 twist rate and have heard no complaints. The other part of your question, from my expeirence with sendero's, they are alot like weatherby's, almost like a freebore. My shooting buddy has a sendero 7RUM and he can load out to just shy of 4 inches and still not hit the lands. In my sendero 300RUM I could load out to 4 inches and not hit the lands. You might try emailing Walt Berger about the twist rate or maybe Brian Litz will chime in here??? Good luck

Also if you look on this forum you will find there is a new bullet company out there building a 200gr bullet for the 7MM, I think it requires a 1/9 twist rate but will work with your 1/9.5

Yeah I'd have to say that is common. My 7rum is long throated too. Just touching the lands with a 160AB I'm right at 4.00". But I will not have enough bullet in the case to safely load it. My 300rum isn't that long, it's right around 3.83" with the 180 sciroccos.

You will have no problems with the twist, I have the same rifle, and have no problems. You will not be able to reach the lands with this bullet. The ogive is too far back. I load mine to 3.650 with very good results and they will still fit into the mag well. I would also recommend using Hodgdon's US869 powder for this cartridge with any bullet as big or bigger than the 168gr. It works great!

What do you think about US869 and the 160 AB? That is what I'm leaning towards.

You will have no problems with the twist, I have the same rifle, and have no problems. You will not be able to reach the lands with this bullet. The ogive is too far back. I load mine to 3.650 with very good results and they will still fit into the mag well. I would also recommend using Hodgdon's US869 powder for this cartridge with any bullet as big or bigger than the 168gr. It works great!

I had the exact opposite experience with my 700 CDL. I actually burned up the bbl trying to get the Bergers to print any kind of group under 2 inches. I did ladder tests, I did 10 thousandths and 20 thousandths jammed into the lands, and behind the lands. I tried 50 BMG, Retumbo, us869, and H 1000. I finally gave up and tried the 160gr ABs with 93 gr of Retumbo and bingo, shot a half inch group at 100 yards. Used it two seasons on antelope, and I was stupid and believed I could get the Bergers to shoot. I would shoot four or five and clean down to bare metal, never let the bbl get too hot, but alas the groups opened up to 5 - 6 inches, even with the ABs.

I talked to a guy at Berger, one of their balisticians, and he told me that really the only way to know if the bbl on the 700 is twisted at 1 in 9.5 was to actually check it myself. I did that with the cleaning rod method, and it was actually twisted a bit looser that advertised. The guy at Berger said that he'd seen a few 700 with factory bbls twisted looser than advertised, as was the case with mine. He said that 1 in 9 was the Minimum that would stabilize the 180gr.

As far as the AB goes, while it was very accurate in my rifle, the terminal performance was poor at best. I never really checked this out but I'm assuming that they are extremely hard because on the antelope I killed they did not expand AT ALL. I hit one at about 320 yards, hitting a rib on the way in and the exit wound looked like a little bullet hole. I got one at just a bit over 500 yards, again with a rib hit, and a tiny exit wound. That one I also hit at a high raking angle, I put one just in front of the left hind quarter, with no bone hit, there was a tiny exit wound just in front of the right front quarter.

From my experinece my advice would be to not spend too much time on Bergers if you don't chance on an accurate load fairly quickly in that round.

Here are a couple other bullets to look at for your 7RUM, hornady 162gr A-Max, 162gr SST or 162gr match bullet "BTHP". I think barnes makes a 150gr bullet for the 7mm or should I say .284
So many people seem so dead set on shooting berger bullets, yes they do perform, but my personal experience with them is either you get lucky and your gun likes them or you have a custom built gun that is throated just for the bergers. Just my opinion here.

Hodgdon claims 13 fps difference in velocity between -40 and 125 degrees farenheit with the US869 and a 50BMG.

To the authour of this thread: I would try US869 if you end up with a 7mm RUM. I have tried Retumbo, and H1000 along with many other powders, and when shooting the 180, or 168gr Berger VLD I get the best results with US869. Duplicate these loads: 168gr Berger VLD set at 3.650, 101gr. US869, Fed 215 primer
180gr. Berger VLD set at 3.658, 99.5gr. US869, Fed 215 primer

The stated loads are near max psi so work up, but once you're there you will love em. Shoot them @ 500yds and note your group size, then try Retumbo (with charges appropriate for that powder) and watch what happens.